Can someone id this for me?

This double action .38 belonged to my wife's grandfather, and was passed down to her. He had it about the time of WWII if not before, and carried it as a deputy sheriff in Ca according to my father in law.

I tried to narrow down the possibilities from the serial number, but none of the possibilities seem to match, in particular the smooth cylinder latch and the plain knob on the end of the ejector rod look suspicious to me, as well as the lack of marking on the barrel other than that shown above.

Given the appearance, caliber, and grips, it looks like a Police Positive or Police Positive Special. But the serial number ranges for those models don't match, in fact the number/patent date doesn't match for any model I can find information on.

The ejector rod end doesn't look like any I've ever seen on a Colt. I wonder it this was a "lunch bucket special" by someone working in the factory?

Given the appearance, caliber, and grips, it looks like a Police Positive or Police Positive Special. But the serial number ranges for those models don't match, in fact the number/patent date doesn't match for any model I can find information on.

The ejector rod end doesn't look like any I've ever seen on a Colt. I wonder it this was a "lunch bucket special" by someone working in the factory?

Sorry, not much help

No, this is helpful. Clearly this weapon has had some parts replaced on it, from the evidence I've been able to find.

Looking at the patent again, it is Jul 4 1905 and not 1906. I found online that the police positive .38 serial number in 1929 started with 185000. In fact, I cannot find another model with a serial number in that range after 1926, so I initially ruled out Police Positive Special because of the patent date on the top of the barrel.

But the photos of police positive .38's I've seen don't match exactly. Maybe the ejector rod was replaced? There's a lot of wear on this gun, so possibly other markings on the side of the barrel were worn off. I'm not sure how feasible that is. The grips don't match either, but they could have been replaced easily enough too. I took the grip off and found the serial number was scratched on the inside of one of the grips; not sure why someone would do that or if that means anything.

More confusing to me, I've read that .38 special ammunition will not fit in a Police Positive which is chambered for .38 NP or .38 S&W (is that correct?) but a .38 special does fit in this gun and my father in law has fired .38 special with it. But the serial number does not make sense for a Police Positive Special unless it was made before 1926, which in turn doesn't make sense with the 1926 patent date stamped on it. I don't want to try to fire this without knowing exactly what it is. Without ammo this gun weighs 32.3 oz. if that is helpful.

Is it possible this is a Police Positive Special made in 1924 (http://proofhouse.com/colt/index.html), but the barrel was replaced at some point explaining the 1926 date? If it's really a Police Positive, then a .38 special should be too long to fit the cylinder, right?

Thanks for your help--this is interesting and confusing at the same time.

Correct on all points. If it's not chambered for .38 Special, the cartridges won't fit.

As you found,
New Service revolver 1926 Serial # starts with 324000
Pocket Positive 1926 serial # starts with 122501 but not produced in .38 Special.
Police Positive 1926 serial # starts with 166001, jumps from 185000 to 329000 in 1929, but not produced in .38 Special.
Police Positive Special 1926 serial # starts with 325001.

I find it difficult to believe the pistol could receive enough abuse to obliterate the model name on the barrel but not the patent dates. I believe you have a Police Positive Special or New Service revolver that has had the barrel replaced at some point, or possibly one that was put together outside the factory.

It's probably safe to shoot, although you may want to relegate it to collector status. A gunsmith should be able to confirm caliber and safety status for a nominal fee. A call or letter to Colt might reveal more information, but I don't know how much they would charge for the service.

Correct on all points. If it's not chambered for .38 Special, the cartridges won't fit.

As you found,
New Service revolver 1926 Serial # starts with 324000
Pocket Positive 1926 serial # starts with 122501 but not produced in .38 Special.
Police Positive 1926 serial # starts with 166001, jumps from 185000 to 329000 in 1929, but not produced in .38 Special.
Police Positive Special 1926 serial # starts with 325001.

I find it difficult to believe the pistol could receive enough abuse to obliterate the model name on the barrel but not the patent dates. I believe you have a Police Positive Special or New Service revolver that has had the barrel replaced at some point, or possibly one that was put together outside the factory.

It's probably safe to shoot, although you may want to relegate it to collector status. A gunsmith should be able to confirm caliber and safety status for a nominal fee. A call or letter to Colt might reveal more information, but I don't know how much they would charge for the service.

Thanks for your help, I appreciate it. The frame does look more like a New Service to me, which I had originally discounted since the barrel didn't look right. I don't think I will try to fire it without getting it checked out first unless my life depends on it. Since my wife is interested in learning to shoot now, this may be my opening to buy something newer!

From the looks of the gun in the photo, My guess is that it might be an New Model Army and Navy, chamber for the .38 Long Colt. These chambers were bored without any "step" so will accept a .38 Special, even a .357 Magnum, cartridge.

Further, the guns looks as if it were nickeled (chromed?) by an aftermarket service, probably then was the cylinder latch smoothed off and the ejector rod reworked.

Though it might accept .38 Special or .357 Magnum cartridges, DON'T TRY TO FIRE THEM!

Thanks Bob, I appreciate your answer and the warning too. I forgot to mention that the cylinder rotates clockwise (to the right as viewed from the shooter's perspective), which I think is not compatible with the New Model Army and Navy (but am not sure). They do look very much identical otherwise.

Someone over at coltforum.com identified the frame as an early Army Special which has had a new barrel put on sometime after 1927 based on the patent markings. The consensus of opinion there is that the patent markings looked authentic but severely polished, while the model and caliber had been polished off when the gun was refinished, so there's no telling where the barrel came from originally.

Even before reading your warning, I was not really in any hurry to fire this weapon; the cylinder does not lock down completely tight when the hammer is cocked, which I've read it should though I'm not surprised since it's over 100 years old apparently. Is a small amount of looseness in a Colt cylinder a safety issue or just a lack of accuracy issue?

Your comment about the step (or lack of one) in the chamber is interesting because that's something else I knew nothing about. This chambers in this gun are slightly smaller near the barrel end, and there is a definite ridge visible there when you look through the cylinders. Is that an indication that these cylinders might be ok for .38 special? Based on your warning it would be nice to have a positive identification to know exactly what's safe to fire in it. My father in law has fired .38 special in it, but he may just have been lucky. I also chambered a few rounds and they seemed to fit OK but I did not close the cylinder. Any advice you or anyone else can offer in that area is very welcome.

The fact that this gun has no collector value since it's been reworked extensively doesn't really bother me, as it came down through the family and was carried by my wife's grandfather when he was a deputy sheriff in Ca.

In all honesty, I would say, "Leave it at that."
It has been modified so much that it's value resides only in its story.
You know its complete history, and that, in and of itself, is quite valuable. I suggest that you validate and carefully write down its entire history, and keep it with the gun. Start with a Colt's letter, and add service records and the like. Finally, add your anecdotal history, according to what you've been told, and including the names and relationships of your sources.
It's a family heirloom, right? Well, document it and pass it down the line.